Magnetic bubbles are generally cylindrical-shaped regions within a material in which a magnetization vector direction within the bubbles is opposite to a magnetization vector direction in the material outside the bubbles. Materials producing magnetic bubbles are often thin crystalline films, but magnetic bubbles are not limited to such materials.
Magnetic bubbles have been studied primarily as prospects for information storage and processing. Although considerable knowledge has been developed on magnetic bubbles, they have so far not been widely exploited for other uses.
From the extensive literature on magnetic bubbles, the following selections provide basic information on magnetic bubble characteristics, to aid in understanding this invention:
"Formation of Normal and Hard Bubbles by Cutting Strip Domains", by Hideki Nishida, Tsutomu Kobayashi, and Yutaka Sugita, IEEE Transactions on Magnetics, Vol. MAG-9, No. 3, September 1973, pages 517-520. PA1 Magnetic Bubble Technology, 2nd edition, by A. H. Eschenfelder, Springer-Verlag, 1981, title page and pages 70-74. PA1 Ferromagnetodynamics, The dynamics of magnetic bubbles, domains and domain walls, by T. H. O'Dell, Halsted Press Book, John Wiley & Sons, New York, 1981, title page and pages 16-24, 98-114. PA1 "Forced Shear Flow of Magnetic Bubble Arrays", by R. Seshadri and R. M. Westervelt, The American Physical Society, Physical Review Letters, Volume 70, Number 2, Jan. 11, 1993, pages 234-237. PA1 "Commensurate-incommensurate transitions in magnetic bubble arrays with periodic line pinning", by Junmin Hu and R. M. Westervelt, The American Physical Society, Physical Review B, Volume 55, Number 2, Jan. 1, 1997-II, pages 771-774.
My copending patent application No. 09/090,369, filed Jun. 4, 1998, suggests ways that magnetic bubble materials can be exploited to produce motion. It proposes moving bubble material in response to a magnetic field gradient by using a magnetic bubble material that allows, but also resists, magnetic bubble movement within the material.